The disclosure relates to a wireless power charging system, and more particularly to a wireless power transmission apparatus of a wireless power charging system.
In general, various electronic devices are equipped with batteries and driven using power charged in the batteries. In this case, the battery is replaceable with new one, and rechargeable in the electronic device. To this end, the electronic device is equipped with a connector for the connection with an external charging device. In other words, the electronic device is electrically connected with the charging device through the connector. However, as the connector in the electronic device is exposed to the outside, the connector may be contaminated with foreign matters or shorted by moisture. In this case, connection failure occurs between the connector and the charging device, so that the battery in the electronic device may not be charged with power.
In order to solve the above problem, there has been suggested a wireless power charging system to wirelessly charge the electronic device with power. The wireless power charging system includes a wireless power transmission apparatus and a wireless power reception apparatus. The wireless power transmission apparatus wirelessly transmits power and the wireless power reception apparatus wirelessly receives power. The electronic device may include the wireless power reception apparatus, or may be electrically connected with the wireless power reception apparatus. In this case, the wireless power reception apparatus must be arranged within a preset charging area of the wireless power transmission apparatus. In particular, when the wireless power charging system is realized through a resonance scheme, it is important that the wireless power transmission apparatus is designed to have a constant coupling coefficient regardless of the location of the wireless power reception apparatus. Otherwise, the variation range of a transmission power amount to be adjusted in the wireless power transmission apparatus must be increased according to the locations of the wireless power reception apparatus. Accordingly, the realization cost of the wireless power charging system may be increased and the efficiency of the wireless power charging system may be degraded.